Before updating to 1.9, you are strongly recommended to back up your etcd data. Consult the installation procedure you are using (kargo, kops, kube-up, kube-aws, kubeadm etc) for specific advice.

checks for `err == ErrWaitTimeout`, or compare specifically to context errors as needed. A future release will make the `ErrWaitTimeout` error private and callers must use `Interrupted()` instead. If you are returning `ErrWaitTimeout` from your own methods, switch to creating a location specific `cause err` and pass it to the new method `wait.ErrorInterrupted(cause) error` which will ensure `Interrupted()` returns true for your loop. 
  
  The `wait.NewExponentialBackoffManager` and `wa...

### Auth

#### client-go:

- CEL authorizer checks no longer raise runtime errors. Calls to "check" will always return a decision object and the authorization error (if any) can be accessed within expressions using the new decision methods "errored" and "error". ([#118804](https://github.com/kubernetes/kubernetes/pull/118804), [@benluddy](https://github.com/benluddy)) [SIG API Machinery]

* Fixes [#49418](https://github.com/kubernetes/kubernetes/pull/49418) where kube-controller-manager can panic on volume.CanSupport methods and enter a crash loop. ([#49420](https://github.com/kubernetes/kubernetes/pull/49420), [@gnufied](https://github.com/gnufied))

    * https://github.com/kubernetes/autoscaler/releases/tag/cluster-autoscaler-1.13.4 
    * https://github.com/kubernetes/autoscaler/releases/tag/cluster-autoscaler-1.13.3
* Add name validation for dynamic client methods in client-go ([#75072](https://github.com/kubernetes/kubernetes/pull/75072), [@lblackstone](https://github.com/lblackstone))

  * kube-apiserver learned the '--anonymous-auth' flag, which defaults to true. When enabled, requests to the secure port that are not rejected by other configured authentication methods are treated as anonymous requests, and given a username of 'system:anonymous' and a group of 'system:unauthenticated'.
  * Authenticated users are decorated with a 'system:authenticated' group.

- Signatures on scale client methods have been modified to accept `context.Context` as a first argument. Signatures of Get, Update, and Patch methods have been updated to accept GetOptions, UpdateOptions and PatchOptions respectively. ([#88599](https://github.com/kubernetes/kubernetes/pull/88599), [@julianvmodesto](https://github.com/julianvmodesto))...

- Added sum feature to `kubectl top pod` ([#105100](https://github.com/kubernetes/kubernetes/pull/105100), [@lauchokyip](https://github.com/lauchokyip))
- Added the `Apply` and `ApplyStatus` methods to the dynamic `ResourceInterface` ([#109443](https://github.com/kubernetes/kubernetes/pull/109443), [@kevindelgado](https://github.com/kevindelgado))